Declining IQ scores can help to predict depression with age, research finds.
As people’s scores on abstract reasoning tests decline, so their risk of being depressed increases.
Typical abstract reasoning tests involve analysing shapes and symbols for things like patterns and commonalities.
Abstract reasoning is a component of fluid intelligence.
Fluid intelligence refers, roughly speaking, to the raw speed at which the brain works.
This naturally declines with age as the brain slows.
Fluid intelligence is normally contrasted with crystallised intelligence.
People with higher crystallised intelligence tend to have better general knowledge, as it refers to acquired information and skills.
The study included 1,091 adults, who were followed from age 70 through to 79.
They were given tests of abstract reasoning and asked about symptoms of depression.
The results showed both people’s reasoning and their depressive symptoms worsened over time.
However, worse depressive symptoms tended to follow poorer cognitive performance, but the reverse was not true.
This suggests that declines in abstract reasoning could be causing depressive symptoms.
Dr Stephen Aichele, the study’s first author, said:
“Mental health in later life is a topic of increasing importance given aging populations worldwide.
Our findings suggest that monitoring for cognitive decrements in later adulthood may expedite efforts to reduce associated increases in depression risk.”
Symptoms of depression include moodiness, lack of motivation and tiredness.
Depression is also strongly linked to physical symptoms like headaches, stomach aches, dizziness, muscle and leg pain.
Dr Aichele said:
“We hope this research will be of broad interest, both for individuals directly affected by age-related cognitive decline and also for family members and care providers who wish to help older persons adversely affected by changes in mental health.”
The study was published in the journal Psychological Science (Aichele et al., 2018).